Astronomers have seen what could be the most powerful supernova ever detected.

The exploding star was first observed back in June last year but is still radiating vast amounts of energy.

At its peak, the event was 200 times more powerful than a typical supernova, making it shine with 570 billion times the brightness of our Sun.

Researchers think the explosion and ongoing activity have been boosted by a very dense, highly magnetised, remnant object called a magnetar.

This object, created as the supernova got going, is probably no bigger than a major city, such as London, and is likely spinning at a fantastic rate - perhaps a thousand times a second.

But it probably also is slowing, and as it does so, it is dumping that rotational energy into the expanding shroud of gas and dust thrown off in the explosion.

The super-luminous supernova, as it is termed, was spotted some 3.8 billion light-years from Earth by the All Sky Automated Survey for Super Novae (ASAS-SN).

This uses a suite of Nikon long lenses in Cerro Tololo, Chile, to sweep the sky for sudden brightenings. Follow-up observations with larger facilities are then used to investigate targets in more detail.

The intention of ASAS-SN is to get better statistics on the different types of supernovas and where they are occurring in the cosmos.

Astronomers have long been fascinated by these monster explosions and have come to recognise just how important they are to the story of how the Universe has evolved.

Not only do they forge the heavier chemical elements in nature but their shockwaves disturb the space environment, stirring up the gas and dust from which the next generation of stars are formed.

The source star for this reported supernova must have been colossal – maybe 50 to 100 times the mass of our Sun.

Such stars begin very voluminous but then shed a lot of mass in great winds that blow out into space. So, by the time this star ended its life, it was very probably greatly reduced in size.

There are signs that the supernova may be about to fade, and the team have time on the Hubble space telescope in the coming weeks to try to further understand the mechanisms driving the supernova, foreign media reports.